in legend by decree of Zeus hades was to rule the under world perhaps this is it but he ch...

I defiantly think so.

In Mythology it was rolling the die, Zeus got 1st pick, Poseidon 2nd and Hades the unlucky one 3rd.
Zeus being arrogant and stuff ^^' wanted the sky, Poseidon knew Zeus being who he was wanted the sky and that was fine by him Poseidon want the 'land' middle earth and so he got the sea while Hades got the leftover pieces the underworld no one wanted (someone had to rule it)

since this manga references (but doesn't fully use) the mythology my guess is they drew lots and Zeus somehow cheated like you said... looks like the king game ...